.30-06 Springfield, while being a wonderful round in it's own right, has been eclipsed by the more powerful .300WSM & the flatter shooting .308 Winchester....Now, it's pretty much relegated to the ash-heap of history in regards to being "popular".
Still a good choice IMHO...Once you get your ranges and elevations dialed in it can really reach out there....Great hunting round, I doubt there is anything in the lower 48 that you can't take with it. And you can't beat it for knocking shooty
holes through concrete block walls if you need to get to someone on the other side.
One thing I will toss out there though....The Garand and the 1903 are not early "assault rifles"....They are a weapon which has left the scene of warfare due to it's ever changing nature.
They are "Battle Rifles"...Intended to be used to counter lances and swords at close range as well as lob bullets 800 yards across no-mans land.
Warfare changed with the advent of the STG44 (The first actual "Assault Rifle":
Sturmgewehr 1944 - Storming Rifle model of 1944) the lower power round it uses is to provide rifle like performance in a sub-machine gun type package.
In between the Garand they (U.S.) tried the M-14 which would have been innovative and highly serviceable during WW2 & Korea as a Battle Rifle but the extra weight of the .308 Win. round combined with the higher power of an actual rifle round (impossible to fire full auto and hit anything) created instead an idiots answer to the "assault rifle".
The AK-47 was a better weapon for modern warfare and the M-16 had some growing pains to get through before it could be appreciated.
...But that's a different story.